Just found out on iphone-elite team:
What is oneSIM ?

Note: this has nothing to do with the upcoming 'revirginator'. But stay tuned for that!

oneSIM is an "undo" of anySIM 1.1. It reverses the patches made by anySIM 1.1. It's useful to developers, researchers, and testers. BUT end users should read the next section if you haven't yet applied anySIM 1.1. (It will save you one or more unlock counts! Those counts add up...to "5" specifically)

oneSIM un-patches the bytes that anySIM changes, back to their original values It's a useful tool to quickly undo anySIM 1.1, to help further testing.

oneSIM 1.1 is an "undo" ONLY for iPhones patched with anySIM 1.1 owned by developers, researchers, and testers (thank you, testers!)

Download: http://code.google.com/p/iphone-elite/downloads/list